Chacoan Titi, Plecturocebus pallescens
CHACOAN TITI
Plecturocebus pallescens
Geographic Distribution and Habitat
Chacoan titi monkeys (Plecturocebus pallescens) are small primates from South America. They live in the neotropics south of the Amazon Rainforest, spanning southeast Bolivia (Santa Cruz), northwest Paraguay (Chaco), and small patches of southwestern Brazil (Mato Grosso do Sul).
Sometimes known as white-coated titi monkeys or pale titi monkeys, these arboreal primates make their homes in forest patches and galley forests throughout the savannah floodplains, the Chaco scrublands, and swamps in the Pantanal, which is the world’s largest tropical wetland area.
While the Chacoan titi monkeys are wide-ranging in the center of South America, population densities across the region are unevenly distributed due to deforestation of habitats.
When they were discovered, Chacoan titi monkeys were classified as a southern subspecies of the Bolivian gray titi monkey (Plecturocebus donacophilus). In 2002, they were officially recognized as a distinct species: Plecturocebus pallescens.
Size, Weight, and Lifespan
All titi monkeys are considered small primates, with an average weight between 28 and 45 oz (800–1,300g). The exact weight of the Chacoan titi monkey is unknown, but they are assumed to be within a similar range. From nose to tail, Chacoan titi monkeys have an average body length of 28.5 in (72.5 cm), which is similar to the length of the average house cat.
There is no sexual dimorphism between males and females, but there can be very slight differences in their weight and length. The exact lifespan of the Chacoan titi monkey is unknown, but in general titi monkeys can live into their early 20s. In captivity, they can live over 25 years.
Appearance
Chacoan titi monkeys are small, stealthy primates. They have small round ears, hazel-brown eyes, flat noses, and thin lips.
These monkeys stand out from other titi monkeys because of their white fur color with black undertones, which is the reason for their “white-coated” and “pale” nicknames. Among the trees, the Chacoan titi monkey looks ghost-like compared to similar species with darker pelage. Their white fur is also soft and dense and covers their entire body and long tail. Around their faces, their fur is a light brown color.
Diet
Titi monkeys are primarily fruit-eaters, but the Chacoan titi monkey also enjoys leaves, seeds, and insects. They start foraging during the early morning hours and continue throughout the day, with a midday rest break.
Chacoan titi monkeys will chew on leaves from flowering vines, shrubs, and trees, and will then rub the chewed leaves all over their bodies. The reason for this behavior is not concretely known but researchers believe the plants may have the ability to repel insects.
Behavior and Lifestyle
Chacoan titi monkeys are arboreal and diurnal omnivores that live in small familial groups. They keep small home ranges between 4 and 74 acres (1.5–30 ha). During the day when they are active, their day ranges average 0.3–1 mi (0.5–1.5 km).
In their small groups, adult males and females live with their offspring. They show affection by tail entwining, which is when two monkeys—most often an adult male and female—wrap their tails around each other. They entwine their tails when they are sitting next to each other, whether they are awake or asleep. Family members also strengthen their bonds by grooming each other, which is a common activity during their daily midday rest.
“Titi” means marmoset in Spanish.
The Chacoan titi monkey is named after the Chaco region in South America.
Chacoan titi monkeys live in small bonded groups of two to five individuals, including a monogamous adult male and female pair and their young.
They spend their days traveling through the forest canopy in search of fruits, seeds, leaves, and insects. Their small bodies make quick, stealthy movements between branches, using all four limbs to walk or jump.
Chacoan titi monkeys are territorial and make loud early morning duet calls to defend their family and home ranges. To avoid predators at night, the group sleeps higher up in the canopy compared to the lower canopy, where they spend their days. They find branches with lots of vegetation coverage and will often return to the tree every night.
The Chacoan titi monkey has an air sac in their larynx, which enables them to make loud ear-piercing vocalizations. All titi monkeys are more vocal than most other Latin American monkeys, and their vocalizations have been observed to be more complex than other primate species. They make a variety of vocalizations when they are in distress, playing, defending their territory, and bonding. In the early mornings, pairs of titi monkeys often duet with other pairs.
Titi monkeys make both low-pitched and high-pitched vocalizations. Low-pitched calls are made when they are communicating with group members and defining their home ranges and include moans, chirrups, honks, and grunts. Their high-pitched calls are made when they are foraging, feeling agitated, or in a dangerous situation. When predators are around, researchers have found that titi monkeys make sequences of warning calls that can vary in duration and frequency, depending on the species of the predator.
Chacoan titi monkeys live in pair-bonded groups including a monogamous adult male and female and their young.
Females are sexually mature by the time they are two years old and start reproducing around the time they are four years old. They give birth to one offspring a year after a 160-day gestation period, with births typically occurring between November and March. Young are weaned by the time they are eight months old and will leave the family group once they are two to three years old.
Besides nursing, mothers provide little parental care. Infant titi monkeys need to be carried during their first few months, but the mother typically only does this for the first week and then sporadically throughout the infant’s youth.
Male titi monkeys play a more active role in child care, providing all protection and carrying young on their back as they move throughout the trees. Research found that young titi monkeys experience more stress when they are separated from their fathers, as opposed to being separated from their mothers.
With a seed-heavy diet, titi monkeys help regenerate forests and encourage new plant growth through seed dispersal.
Chacoan titi monkeys are also a food source for predators like birds of prey, big cats, and other local species of monkeys.
The International Union for Conservation of Nature lists Chacoan titi monkeys as Least Concern Conservation Status (IUCN, 2015), appearing on the IUCN Red List of Threatened Species.
Chacoan titi monkeys cover a wide range in central South America. Although they are listed as Least Concern, their habitats are threatened by forest fires and deforestation for agriculture and cattle ranching, primarily in the Chaco area of Paraguay and Bolivia.
Chacoan titi monkeys are captured as pets in Paraguay and hunted by Izoceno indigenous communities near the Kaa-Iya del Gran Chaco National Park. Predators like raptors (birds of prey), felids (large cats), and other species of monkeys are additional threats throughout their habitats.
The Chacoan titi monkey is listed in Appendix II of the Convention on International Trade in Endangered Species (CITES), an international agreement between governments whose goal is to ensure that international trade in specimens of wild animals and plants does not threaten their survival.
The Chacoan titi monkey is protected in three national parks—Rio Negro, Chovoreca, and Defensores del Chaco—as well as the Fortin Patria Private Reserve, the Paraguayan Pantanal Reserve, and the protected areas of Kaa-Iya, San Matías, and Otuquis.
Part of the Chacoan titi monkey’s southern range remains unprotected in the Humid Chaco, which is an area of tropical grasslands, savannas, and shrublands.
- https://neprimateconservancy.org/bolivian-gray-titi/
- https://nationalzoo.si.edu/animals/titi-monkey
- https://frontiersinzoology.biomedcentral.com/articles/10.1186/s12983-016-0142-4
- https://bioone.org/journals/neotropical-primates/volume-19/issue-1/044.019.0102/Distribution-Habitat-and-Status-of-the-White-Coated-Titi-Monkey/10.1896/044.019.0102.full
- https://eol.org/pages/51906284
- https://www.bioexplorer.net/animals/mammals/monkeys/chacoan-titi-monkey/
- https://pubmed.ncbi.nlm.nih.gov/28763579/
- https://animalia.bio/white-coated-titi
- https://www.iucnredlist.org/species/41549/192452042
- https://www.gbif.org/species/9401316
Written by Maria DiCesare, February 2023